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US 7,465,782 B2Granted
Method for making polybenzobisoxazole containing fiber
AssigneeE.I. du Pont de Nemours and Company
InventorKiu-Seung Lee
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Abstract
A method of making polybenzobisoxazole containing fiber by use of a non-polybenzobisoxazole polymer, hydroxylating the polymer, forming the polymer into a fiber and heating the fiber wherein ring closure occurs in the hydroxylated polymer.
Claims10
A method of making polybenzobisoxazole containing fiber comprising the steps of:
- a) forming a polymer solution comprising a solvent and a polymer having the structure:
- wherein
- Ar1 is
- Ar2 is
- b) contacting the polymer solution of a) with a oxidizing agent in the presence of an alkyl carboxylic acid which provides oxygen atoms to hydroxylate at least a portion of Ar1, in forming a hydroxylated polymer with ortho hydroxyl groups,
- c) forming a fiber from the hydroxylated polymer of step b),
- d) heating the fiber to form ring closure of at least a portion of ortho-hydroxyl groups.
4 more elements
Dependencies are inferred from the claim text.